Apple Flavonoids Suppress Carcinogen‐Induced DNA Damage in Normal Human Bronchial Epithelial Cells

Vazhappilly, Cijo George; Rupasinghe, H.P. Vasantha

doi:10.1155/2017/1767198

Cited by 33 publications

(30 citation statements)

References 45 publications

(64 reference statements)

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“…It has been shown that antioxidants may protect DNA from H 2 O 2 -mediated damage, however some may actually escalate oxidative damage caused by H 2 O 2, or may even be genotoxic themselves [34] , [35] . The comet assay, a useful method for detecting DNA strand breaks at the single-cell level, has been used by us to study the impact of exogenous GSH and catechins on DNA integrity in both mentioned situations.…”

Section: Resultsmentioning

confidence: 99%

The relationship between standard reduction potentials of catechins and biological activities involved in redox control

et al. 2018

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Redox homeostasis involves factors that ensure proper function of cells. The excess reactive oxygen species (ROS) leads to oxidative stress and increased risk of oxidative damage to cellular components. In contrast, upon reductive stress, insufficient ROS abundance may result in faulty cell signalling. It may be expected that dietary antioxidants, depending on their standard reduction potentials (E°), will affect both scenarios. In our study, for the first time, we systematically tested the relationship among E°, chemical properties, and biological effects in HT29 cells for a series of structurally different catechins and a major endogenous antioxidant – glutathione (GSH), at both physiological and dietary concentrations. Among chemical antioxidant activity tests, the strongest correlation with E° was seen using a DPPH assay. The values of E° were also highly correlated with cellular antioxidant activity (CAA) values determined in HT29 cells. Our results indicated that physiological concentrations (1–10 µM) of tested catechins stabilized the redox status of cells, which was not exhibited at higher concentrations. This stabilization of redox homeostasis was mirrored by constant, dose and E° independent CAA values, uninhibited growth of HT29 cells, modulation of hydrogen peroxide-induced DNA damage, as well as effects at the genomic level, where either up-regulation of three redox-related genes (ALB, CCL5, and HSPA1A) out of 84 in the array (1 µM) or no effect (10 µM) was observed for catechins. Higher catechin concentrations (over 10 µM) increased CAA values in a dose- and E°-dependent manner, caused cell growth inhibition, but surprisingly did not protect HT29 cells against reactive oxygen species (ROS)-induced DNA fragmentation. In conclusion, dose-dependent effects of dietary antioxidants and biological functions potentially modulated by them may become deregulated upon exposure to excessive doses.

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Section: Resultsmentioning

confidence: 99%

The relationship between standard reduction potentials of catechins and biological activities involved in redox control

et al. 2018

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“…The biological effects of apple phenolic compounds are also of interest. Flavonoids extracted from apple peel were implicated in the suppression of breast cancer and the growth of carcinogenic cells in the bronchi [George & Rupasinghe, 2017;Loung et al, 2019]. In turn, Zielińska et al [2019] proved the potential benefits of apple-derived polyphenols in modulating inflammation at the intestinal level.…”

Section: Apple Phenolic Compounds -The Biological Effectsmentioning

confidence: 98%

Phenolic Compounds from Apples: Reviewing their Occurrence, Absorption, Bioavailability, Processing, and Antioxidant Activity – a Review

Starowicz¹,

Piskuła²,

Achrem–Achremowicz³

et al. 2020

Pol. J. Food Nutr. Sci.

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and high environmental pollution. The consumption of fruits and vegetables is highly recommended to support the body in this respect. The main antioxidants found in fruits and vegetables are A, E, and C vitamins; β-carotene; lycopene; and a diverse group of compounds named phenolics. Therefore, it is hard to select one specific compound responsible for health benefits. That is why, Ohr [2004] stated that "scientists are currently studying how mixtures of antioxidants … work together. They are looking for synergistic effects among individual antioxidants." The most important group of antioxidants is the phenolic compounds (Figure 1). They are organic chemical compounds with at least one phenol unit, represented by, i.a., tannins (hydrolysable and condensed), flavonoids, and lignans. Phenolic compounds can be found in a variety of plant species. Their high content is correlated with antioxidant activity, which decreases the risk of coronary disease and protects against neurodegeneration [Giacalone et al., 2015]. The positive effect of flavonoids on memory improvement was also studied [Whyte & Williams, 2011]. Of 12 epidemiological surveys about coronary heart disease risk assessment compared by Arts & Hollman [2005], seven demonstrated the protective effects of a diet enriched with polyphenols. An inverse relationship has also been determined between poly

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“…Pretreatment with AF4 reduced the ROS level with an increase in anti-oxidant enzymes. Further, AF4 reduces DNA damage and enhanced protection against carcinogens by facilitating DNA repair mechanisms [168]. A study by Kaewmool et al, showed both anti-inflammatory and apoptotic effects of C3G in PC-12 cells.…”

Section: Cyanidinmentioning

confidence: 98%

Dietary Flavonoids in p53—Mediated Immune Dysfunctions Linking to Cancer Prevention

et al. 2020

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The p53 protein plays a central role in mediating immune functioning and determines the fate of the cells. Its role as a tumor suppressor, and in transcriptional regulation and cytokine activity under stress conditions, is well defined. The wild type (WT) p53 functions as a guardian for the genome, while the mutant p53 has oncogenic roles. One of the ways that p53 combats carcinogenesis is by reducing inflammation. WT p53 functions as an anti-inflammatory molecule via cross-talk activity with multiple immunological pathways, such as the major histocompatibility complex I (MHCI) associated pathway, toll-like receptors (TLRs), and immune checkpoints. Due to the multifarious roles of p53 in cancer, it is a potent target for cancer immunotherapy. Plant flavonoids have been gaining recognition over the last two decades to use as a potential therapeutic regimen in ameliorating diseases. Recent studies have shown the ability of flavonoids to suppress chronic inflammation, specifically by modulating p53 responses. Further, the anti-oxidant Keap1/Nrf2/ARE pathway could play a crucial role in mitigating oxidative stress, leading to a reduction of chronic inflammation linked to the prevention of cancer. This review aims to discuss the pharmacological properties of plant flavonoids in response to various oxidative stresses and immune dysfunctions and analyzes the cross-talk between flavonoid-rich dietary intake for potential disease prevention.

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Apple Flavonoids Suppress Carcinogen‐Induced DNA Damage in Normal Human Bronchial Epithelial Cells

Cited by 33 publications

References 45 publications

The relationship between standard reduction potentials of catechins and biological activities involved in redox control

The relationship between standard reduction potentials of catechins and biological activities involved in redox control

Phenolic Compounds from Apples: Reviewing their Occurrence, Absorption, Bioavailability, Processing, and Antioxidant Activity – a Review

Dietary Flavonoids in p53—Mediated Immune Dysfunctions Linking to Cancer Prevention

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